A set of final examination grades in a calculus course was found to be normally distributed with a mean of 69 and a standard deviation of 9.What percentage of students scored between 65 and 89?
A)65.68%
B)100%
C)98.68%
D)33.00%

Question

Quizplus · Accepted Answer

Using the properties of the normal distribution, we calculate the z-scores for 65 and 89. The z-score for 65 is (65-69)/9 = -0.44, and for 89 is (89-69)/9 = 2.22. Using the standard normal distribution table, the percentage of students scoring between these z-scores is approximately 65.68%.

A Set of Final Examination Grades in a Calculus Course